1. Field of the Invention
The present invention relates to cleaning portions of pipe in the areas where adjacent end sections of pipe have been welded together to form a pipeline or the like. More specifically, the present invention provides a new and improved pipe weld cleaner and control mechanism to regulate and control movement of a cleaning head as it moves along and about the welded pipe end portions while cleaning those end portions after they have been welded together.
2. Description of the Related Art
Pipelines have been for a number of years laid on the submerged floors of bodies of water from pipe laying barges. On the pipe-laying barge, the pipeline length was formed by welding successive lengths or sections of pipe sequentially in an end-to-end fashion to previously welded sections at an end portion of the pipeline. The pipe sections were typically covered with concrete or some other protective coating along their lengths except for the exposed metal end sections. The welded sections extended from the pipe-laying barge into the body of water and were laid or deposited in or on the floor of the body of water. After a length of pipe was welded to the end of the pipeline, and before its entry into the body of water, it has been the practice to clean the areas where the weld occurred so that a corrosion-resistant coating or film of a suitable synthetic resin could be applied. It was also typical after application of the corrosion coating film to apply a protective coating over the corrosion resistant film. U.S. Pat. Nos. 4,909,669; 5,328,648; 5,804,093; 5,900,195 and 6,402,201, owned by the assignee of the present application, are examples of end portion protective covers or coatings for such a purpose.
So far as is known, previous machines for pipe cleaning in the area of the welded ends have taken the form of a set of pipe-enclosing collar rings mounted around the circumference of the pipe. The collar rings were longitudinally spaced from each other along the pipe, with the most recently welded section located between them. One or more, usually several, blast material applicator heads and removal heads or evacuators were mounted between the collar rings at selected locations about the periphery of a section of the pipe.
The applicator heads and the removal heads were moved in a circumferential arcuate path about an incremental length of the pipe until the full circumferential extent of that section of the length of the pipe has been cleaned. These previous cleaning machines have had problems in movement control. Several crewmembers were required for each machine. In addition to an operator controlling starting and stopping of the machine, typically there were at least two other crew members involved in movement of the cleaning heads to successive sections of the pipe lengths to be cleaned. After a certain length of pipe was cleaned, the mounting rings had to be opened and moved to a new location for additional cleaning. Further, each individual blast material applicator head was provided with a separate supply hose and each individual material removal head with a separate removal hose or tube.
Thus, there were several cleaning crew members and a number of hoses in a relatively small area, where a number of applicator heads and removal heads were moving in rotary paths about the circumference of a short length of the pipe section. As a result, movement control was a problem. Also, cleaning operations were time consuming and labor intensive. In addition there were some safety concerns due to the close proximity of some of the work crew to the rotating equipment and supply hoses.